1. Field of the Invention
This invention relates to a novel anticoagulating substance, a process for preparing the substance, an anticoagulant comprising the substance as an effective component, and a medical composition.
2. Description of the Prior Art
The coagulation of blood is considered to start from the development of thromboplastin activity, followed by activation of factor X and V in the blood, further activation of prothrombin into thrombin and final conversion of fibrinogen into fibrin by the action of the thrombin.
For the treatment of diseases ascribed to the coagulation, it is effective to use a substance which is able to impede or deactivate various coagulation factors which take part in the coagulation mechanism, i.e. an anticoagulating substance. Currently known anticoagulating substances include heparin, heparin cofactor-II, antithrombin-III, .alpha..sub.2 -macroglobulin, .alpha..sub.1 -trypsin inhibitor, C.sub.1 -esterase inhibitor, protein C and the like.
In recent years, Chris P.M. Reutelingsperger et al found out, as reported in Eur. J. Biochem., 151, 625-629 (1985), a novel substance having the anticoagulating activity and a molecular weight of 32 kDa from arteries of the human umbilical cord.
However, most known anticoagulating substances have been merely confirmed to exist and it is only heparin that is now in use as a medicine. However, since heparin has the side effect of a tendency toward bleeding, the manner and amount of use are very strictly limited. Thus, it is not satisfactory as the anticoagulating agent from the standpoint of safety.
The substance found by Reutelingsperger et al is completely different from the substance of the invention for the reason described hereinafter. In addition, the activity of the substance has been determined only in the form of a mixture and thus, such a substance is not considered to be useful for practical service.
Accordingly, there is a demand of development of better anticoagulants.